Machine for packaging articles into bags made of flexible material

ABSTRACT

A machine for packaging articles into bags made of heat-sealable flexible material starting from a reel of a continuous web having two superimposed flat layers mutually permanently joined along one side and provided—along the other side—with an openable closure. The machine includes a device for supplying the web having a pair of superimposed parallel guide rollers arranged transversely on opposite sides with respect to the web and whose angular position with respect to the advancement direction of the web is adjustable. The two guide rollers have a superficial shape suitable to avoid both the formation of irregularities of the web—such as folds and creases—as well as the damaging of the openable closure.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to Italian Patent Application No. 102016000094253 filed on Sep. 20, 2016, the entire disclosure of which is incorporated herein by reference.

FIELD OF THE INVENTION

The present invention refers to the packaging of articles into bags made of heat-sealable flexible material, obtained starting from a reel of a continuous web having two superimposed flat layers. Webs thus made can be typically constituted by a flat tubular film made of mono-folded plastic material, with the two superimposed layers joined to each other in a sealed manner along the longitudinal folding edge and possibly also along the opposite longitudinal edge. In any case, the film is heat-sealable and can be entirely made of plastic material or it can be formed by materials of various types coupled with the plastic material.

STATE OF THE PRIOR ART

Patents EP-0926069B1 and EP-2534053B1 in the name of Applicant describe a machine for packaging articles into a bag made of heat-sealable flexible material of the type defined above, comprising a device for supplying the web along an advancement direction towards an assembly which transversely cuts the web into subsequent web lengths, spreads the layers of each web length apart for the introduction of the articles thereinto, and then heat-seals the web length transversely.

The present invention represents an improvement of the invention subject of the aforementioned patents with the aim of expanding the field of application thereof further. As a matter of fact, the specific purpose of the invention is to enable the use of the packaging machine with film reels whose longitudinal edge opposite to the folding edge is provided with an openable closure. Such closure, for example of the type commercially referred to as “mini-grip”, is typically made up of a thin longitudinal rib projecting from the inner face of one of the layers and elastically pressure-inserted into a longitudinal complementary groove obtained on the inner face of the other layer. When the web thus made is wound into a reel, the thickness and thus the diameter of the area corresponding to the openable closure is larger than the diameter of the opposite area. I.e. the reel has a more or less conical shape, thus implying that when the web is unwound it tends to deviate on the side of lower conicity and with the practical impossibility to be correctly supplied—by the packaging machine—to the cutting, spreading apart and heat-sealing assembly.

SUMMARY OF THE INVENTION

The present invention provides a simple and efficient solution to the aforementioned technical problem due to the fact that the packaging machine of the type defined above is mainly characterised by the fact that the supply device comprises a pair of web guiding parallel rollers arranged transversely on opposite sides with respect to the web and whose angular position with respect to the advancement direction of the web is adjustable.

More precisely, one end of the pair of guide rollers, for example corresponding to the permanent joining side of the web layers, is pivoted to an orienting axis orthogonal to the plane of the web, and the opposite end is connected to a device for the angular displacement of the pair of rollers around the aforementioned orienting axis.

Thanks to this solution idea, the web provided with the previously mentioned lateral openable closure can be efficiently deviated from the direction that it would tendentially take due to the conicity of the reel being unwound, towards the correct direction of advancement to the operative assembly of the machine. The degree of the deviation, or the degree of adjustment of the angular position of the pair of rollers, will obviously be proportional to the thickness of the reel and may progressively reduce as it finishes.

In order to perform the adjustment, the device for the angular displacement of the guide rollers is conveniently of the screw-and-nut linear type, actuatable manually or possibly even automatically and synchronously with the unwinding of the web.

The adjustment of the angular position of the guide rollers may normally lead to the occurrence of irregularities on the web such as undulations, folds and creases, for example, immediately upstream of the rollers with respect to the advancement direction. In order to avoid such defects, the invention provides for various alternative solutions for the elimination thereof: for example, there can be provided a superficial helical channel or race and at least one annular radial groove obtained on the lower guide roller and possibly also on the upper guide roller.

The helical race/s have the effect of spreading the film and eliminating creases, and the annular races have the function of housing the openable closure thus preventing the damaging thereof due to compression between the two rollers, as well as further compensating the greater thickness of the film and reducing the misalignment thereof.

Alternatively, the surface of the upper guide roller can be fully or partly elastically yieldable.

According to a further characteristic of the invention the configuration of the guide rollers can also be provided, partly or fully, for a pair of web rollers—respectively for drawing and abutting the web—arranged downstream of the guide rollers with respect to the direction of advancement towards the cutting, spreading apart and heat-sealing assemblies of the machine.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be described in detail with reference to the attached drawings, provided purely by way of non-limiting example, wherein:

FIG. 1 is a schematic perspective view of a packaging machine incorporating a first embodiment of the invention,

FIG. 2 shows an enlarged scale of a part of FIG. 1,

FIG. 3 is a partial front elevational and larger-scale view of FIG. 2,

FIG. 4 shows a variant of FIG. 2, and

FIG. 5 is a perspective view analogous to FIGS. 2 and 4 of a further variant of the invention.

DETAILED DESCRIPTION OF THE INVENTION

Initially with reference to FIG. 1, a packaging machine according to the invention essentially comprises, as known, a structure 1 in an upper area on which there is arranged a filling station generally indicated with 2, into which articles—to be packaged into flexible bags produced by the machine—are supplied, for example in a mechanised manner by means of conventional methods (not illustrated). Such flexible bags are generated starting from a continuous web made of heat-sealable flexible material 3 that is unwound from a reel 4 supported by the structure 1 and transferred to the filling station 2 by means of a supply device generally indicated with 5.

The supply device 5, which constitutes the core of the invention, is expressly configured for the use of the packaging machine with webs 3 of the so-called “mini-grip” type: as known, this is a film made of heat-sealable plastic material mono-folded along a longitudinal edge and provided with an openable closure 6, better observable in FIG. 3, along the opposite longitudinal edge. The longitudinal edge of the film adjacent to the closure 6 can be opened or closed, i.e. heat-sealed and thus sealed, and provided with a dashed pre-cut that can be torn to enable access to the closure 6 and thus the opening of the bag to remove the articles packaged therein.

The openable closure 6 is formed—in a per se known manner—by a thin and wire-like continuous longitudinal relief projecting from the inner face of one of the superimposed layers of the web 3 and elastically pressure-engaged in a complementary longitudinal race formed on the inner face of the other layer. Due to the presence and thus the thickness—though limited—of the openable closure 6, the reel 4 has a general slightly conical conformation, obviously with larger diameter on the closure 6 side.

The operative assembly of the packaging machine is not visible in the drawings and it will not be described in detail, given that it is generally known from the aforementioned patents EP-0926069B1 and EP-2534053B1. For the purposes of the present invention, it is sufficient to point out that such assembly transversely cuts the web 3 into subsequent web lengths, spreads the layers of each web layer apart for the introduction of articles thereinto, and then heat-seals the web length transversely. The bags thus obtained have three permanently sealed sides and the fourth side is sealed in an openable fashion by means of the closure 6.

According to the invention, the supply device 5 is configured so as to compensate the previously mentioned conicity of the reel 4, arising from the presence of the openable closure 6. According to its peculiar characteristic, the supply device 5 consists in a pair of idle and orientable guide rollers arranged between the reel 4 and the operative assembly 2 of the machine. More in detail, and with reference to FIG. 2 in particular, the pair of rollers consists in a lower roller 7 and an upper roller 8 vertically superimposed to each other and arranged transversely and on opposite sides with respect to the web 3 to deviate it from a generally horizontal path, in the advancement direction indicated by the arrow F, to a generally vertical path.

The rollers 7 and 8, whose particular superficial conformation will be described in detail hereinafter, can be adjusted in angular position with respect to the advancement direction F, and more precisely so as to vary the perpendicular condition of the axis of the rollers 7, 8 with respect to the longitudinal edges of the web 3. In detail, the rollers 7 and 8 are carried in a freely rotatable manner by a pair of common end supports 9, 10 of which the first, located on the opposite side with respect to the openable closure 6 of the web 3, is rotatably supported by the structure 1 around a vertical axis indicated with A, orthogonal to the horizontal plane of the web 3. The other support 10, thus located on the openable closure 6 side, can be displaced in the direction indicated with B, parallel to the advancement direction F of the web 3, by means of a control device 11 of the linear type, for example of the screw 12 and nut 13 type. The rotation of the screw 12, performed manually by means of a knob 14, causes the angular displacement of the rollers 7, 8 around the axis A by the degree required to compensate the conicity of the reel 4 due to the presence of the openable closure 6. This adjustment can be carried out, progressively as the reel 4 reduces, at intervals even continuously, manually or even automatically and provided with a device for detecting the diameter of the reel 4.

Thus, the effect of the angular adjustment of the two guide rollers 7, 8 is to compensate the conicity of the reel 4 maintaining the web 3 constantly directed in the correct advancement direction F, without deviations that can cause errors or malfunctioning by the operative assembly 2 of the machine.

Should the web 3 be deviated in the correct advancement direction F, the correct directing of the web 3 performed by the rollers 7, 8 would however cause both the occurrence of irregularities on the web 3 such as folds, undulations and creases as well as potential compressions of the openable closure 6 which could thus be damaged. To this end, the invention provides for various alternative configurations of both rollers 7, 8, described hereinafter, which enable overcoming this problem.

The lower roller 7 is conveniently formed with a superficial helical channel or race 15, having the purpose of spreading the web 3 thus avoiding creases. Furthermore, the lower roller 7 is formed, on the support 10 side, with an annular radial groove 16 having the purpose of receiving the openable closure 6 during the passage of the web 3, as represented more in detail in FIG. 3. Given that the web 3 may come in various widths, all applicable with the packaging machine according to the invention, the lower roller 7 can be made with further identical annular grooves 16 spaced as a function of the various widths of the web 3, and also as a function of the position (right or left) of the closure 6. Thus, such grooves 16 have the function of preventing the damaging of the openable closure 6 due to the compression of the web 3 between the rollers 7, 8, as well as further reducing the thickness difference between the part of the film 3 carrying the closure 6 and the remaining part, to the advantage of sliding homogeneity of the web 3.

The upper roller 8, which is conveniently pressing and thus abutting the web 3 against the lower roller 7, can be provided with an at least partly elastically yieldable surface. In such case, the roller 8 has a soft cover 17 for example made of rubber, sponge or felt material, which also enables releasing the air trapped between the two layers of the web 3 when it is passing. The soft cover 17 can be applied in a uniform and continuous manner, as represented in FIG. 2, or according to a helical path for example corresponding to that of the helical channel 15 of the lower roller 7. Alternatively, the upper roller 8 may also be formed with superficial helical channel or race 15 and with one or more annular radial grooves 16 analogous and corresponding to those of the lower rollers 7, as represented in the variants of FIGS. 4 and 5. The latter figure also shows a further implementation of the invention according to which the machine further includes, immediately downstream of the pair of guide rollers 7, 8, a further pair of rollers—respectively of the drawing 18 and abutment 19 type—in which the first is usually driven and the second one, arranged facing the first, is idle. At least one of these rollers 18, 19, and preferably both, have the same superficial conformation as the rollers 7, 8, i.e. helical channels 15 and annular grooves 16.

Obviously, the construction details and the embodiments may widely vary with respect to what has been described and illustrated, without departing from the scope of protection of the present invention as defined in the claims that follow. 

What is claimed is:
 1. A machine for packaging articles into bags made of heat-sealable flexible material starting from a reel of a continuous web having two superimposed flat layers mutually permanently joined along one side, wherein the machine comprises: a supply device for supplying the web along an advancement direction towards an assembly for transversely cutting the web into subsequent web lengths, spreading the layers of each web length apart for the introduction of the articles thereinto, and then transversely heat-sealing the web length; and the supply device comprising a pair of parallel rollers for guiding the web arranged transversally on opposite sides of the web and whose angular position with respect to the advancement direction of the web is adjustable.
 2. The machine according to claim 1, wherein one end of said pair of guide rollers is pivoted to an orienting axis perpendicular to the plane of the web and the opposite end thereof is connected to an angular displacement device of the pair of guide rollers around said orienting axis.
 3. The machine according to claim 2, wherein said angular displacement device is of the screw-and-nut linear type.
 4. The machine according to claim 2, wherein said guide rollers are mutually superimposed vertically so as to deviate the web from a horizontal path to a vertical path, and said orienting axis is vertical.
 5. The machine according to claim 4, wherein a lower roller of said pair of guide rollers is provided with a superficial helical race.
 6. The machine according to claim 4, wherein said lower roller of said pair of guide rollers is provided with at least one annular radial groove.
 7. The machine according to claim 5, wherein said lower roller of said pair of guide rollers is provided with at least one annular radial groove.
 8. The machine according to claim 7, wherein said lower roller of said pair of guide rollers is provided with a plurality of longitudinally spaced-apart annular radial grooves.
 9. The machine according to claim 4, wherein an upper roller of said pair of guide rollers is provided with an at least partly elastically yieldable surface.
 10. The machine according to claim 9, wherein said upper roller of said pair of guide rollers is entirely covered by a soft material.
 11. The machine according to claim 9, wherein said upper roller of said pair of guide rollers is covered by a soft material along a helical path.
 12. The machine according to claim 5, wherein said upper roller of said pair of guide rollers is provided with a superficial helical race.
 13. The machine according to claim 6, wherein said upper roller of said pair of guide rollers is provided with a superficial helical race.
 14. The machine according to claim 6, wherein said upper roller of said pair of guide rollers is provided with at least one annular radial groove facing said at least one annular radial groove of the lower roller.
 15. The machine according to claim 8, wherein said upper roller of said pair of guide rollers is provided with a plurality of annular radial grooves facing said annular radial grooves of the lower roller.
 16. The machine according to claim 1, wherein said guide rollers are idle rollers.
 17. The machine according to claim 1, wherein a pair of respectively drawing and abutment rollers is provided downstream of said pair of guide rollers with respect to the advancement direction of the web, at least one of which has a superficial helical race.
 18. Machine according to claim 17, wherein, at least one of said drawing and abutment rollers has at least one annular radial groove.
 18. A machine for packaging articles into bags made of heat-sealable flexible material starting from a reel of a continuous web having two superimposed flat layers mutually permanently joined along one side, wherein the machine comprises: a supply device for supplying the web along an advancement direction towards an assembly for transversely cutting the web into subsequent web lengths, spreading the layers of each web length apart for the introduction of the articles thereinto, and then transversely heat-sealing the web length, the supply device comprising a pair of vertically superimposed parallel rollers for guiding the web, said rollers being arranged transversally on opposite sides of the web and an upper roller of said pair of rollers pressing the web against a lower roller of said pair of rollers, and wherein an angular position of said rollers with respect to said advancement direction of the web is adjustable.
 19. The machine according to claim 18, wherein said lower roller is provided with a superficial helical race and with at least one annular radial groove. 